【作者】 孙杰；

【导师】 刘军；

【作者基本信息】 东北大学 ， 通信与信息系统， 2010， 硕士

【摘要】 DTN网络是一种新型的自组织网络,由于其长延时、高动态拓扑、节点分布稀疏、频繁断路等网络特性,造成难以维持稳定的端到端路径。从而使得传统的有线和无线网络路由协议无法应用,因此,有效可靠的路由策略成为DTN网络中的关键问题。提出一种基于存储-携带-转发机制的DTN网络路由算法,源节点不以建立到目的节点的路由为发送数据的前提,在无法建立端到端路由时,选择合适的节点作为数据携带节点,称为“中继节点”,把数据传送到中继节点,中继节点存储数据,寻找目的节点或更优中继节点进行数据转发,经过逐跳携带转发,最终到达目的节点。在存储-携带-转发过程中,充分利用网络频繁变化的特点,针对到目的节点或更优中继节点的短时局部连通路径,采用Ad Hoc网络路由策略,建立路由,提高网络性能。针对网络节点运动可预知和不可预知两种情况,分别设计中继节点的选择策略：在节点运动可预知的情况下,建立虚拟欧式空间,将网络环境划分为N个区域,通过己知的节点运行规律,离线计算出每个节点的虚拟坐标值,在通信范围内选择与目的节点之间虚拟欧氏距离最小的节点,作为数据中继节点；针对节点运动未知的DTN网络,通过节点周期广播Hello报文,节点根据是否接收到其它节点的Hello报文为依据,实时维护节点传输概率信息表,传输数据时,在通信范围内选择与目的节点之间传输概率最大的节点,作为数据中继节点。通过NS2网络模拟软件对算法进行仿真,从网络成功投递率、网络流量和时延三个方面与AODV路由协议、PRoPHET路由协议进行对比,结果表明：所提出的算法具有较好的性能,适合在DTN网络中应用。更多还原

【Abstract】 DTN network is a new type of mobile Ad Hoc network. Due to its characteristics such as long communication delay, high dynamic topology, sparse distribution of nodes and frequent link break, it is difficult to maintain the stability of end to end path. Therefore, the traditional wired or wireless network routing protocol cannot be directly used in DTN network. Design of effective and reliable routing algorithms has become the key issue in DTN network.A DTN routing algorithm with the thought of "storage-carry-forward" is proposed in this paper. Source nodes don’t establish a complete route to destination nodes to send data packets. However, a source node selects an appropriate node as a data carrier called "relay node" in the context of that the end to end route cannot be established. Under this circumstance, the relay node receives packets, stores them and then finds the destination or a better relay node to forward packets. Through hop-by-hop storage-carry-forward strategy, packet will finally arrive at the destination. In the storage-carry-forward process, routs are constructed by considering characteristics of DTN network. Although DTN network topology is frequently changing, nodes within local area may be strong connected in a short time and thus can provide a path from source or relay nodes to destination or better relay nodes. So Ad Hoc Network routing strategies are used to improve network performance.For the two cases of that motions of DTN nodes are predictable and unpredictable, we design relay node selection schemes respectively. For the case of motions of DTN nodes are predictable, a virtual Euclid space is constructed, which divides the network into N regions. According to motion regularity of nodes, virtual coordinates of each node are calculated off-line. Nodes choose relay nodes with smallest virtual Euclid distance to the destination nodes within their communication range. For the case of motions of DTN nodes are unpredictable, nodes periodically broadcast Hello packets. Nodes real-timely maintain information table of transmission probability to other nodes depending on whether receiving Hello packet from other nodes. Nodes will choose relay nodes with biggest transmission probability to destination nodes when delivering packets.NS2network simulation software is used to analyze the validity and reliability of the proposed DTN routing algorithm. Comparing with AODV routing protocol, PRoPHET routing protocol in terms of three metrics, network successful delivery ratio, network traffic and communication delay, simulation results show that the proposed algorithm has better performances and it’s suitable for DTN network applications.更多还原